Fixed the problem that more than one answer.
Thank you for playing. 1,000 downloaded!!
One character of a formula becomes a blank.
The position of a blank is never the same.
Mode
1. 1 digit and 1 digit calculate. Selection from among the four.
2. 1 digit and 1 digit calculate. Direct input.
3. 2 digit and 2 digit calculate. Selection from among the four.
4. 2 digit and 2 digit calculate. Direct input.
2 digit calculate is difficult. Do you answer correctly?
